Ultrahigh-Spatial-Resolution Photon-counting Detector CT Angiography of Coronary Artery Disease for Stenosis Assessment.

Background Coronary CT angiography is a first-line test in coronary artery disease but is limited by severe calcifications. Photon-counting-detector (PCD) CT improves spatial resolution. Purpose To investigate the effect of improved spatial resolution on coronary stenosis assessment and reclassification. Materials and Methods Coronary stenoses were evaluated prospectively in a vessel phantom (in vitro) containing two stenoses (25%, 50%), and retrospectively in patients (in vivo) who underwent ultrahigh-spatial-resolution cardiac PCD CT (from July 2022 to April 2023). Images were reconstructed at standard resolution (section thickness, 0.6 mm; increment, 0.4 mm; Bv44 kernel), high spatial resolution (section thickness, 0.4 mm; increment, 0.2 mm; Bv44 kernel), and ultrahigh spatial resolution (section thickness, 0.2; increment, 0.1 mm; Bv64 kernel). Percentages of diameter stenosis (DS) were compared between reconstructions. In vitro values were compared with the manufacturer specifications of the phantom and patient results were assessed regarding effects on Coronary Artery Disease Reporting and Data System (CAD-RADS) reclassification. Results The in vivo sample included 114 patients (mean age, 68 years ± 9 [SD]; 71 male patients). In vitro percentage DS measurements were more accurate with increasing spatial resolution for both 25% and 50% stenoses (mean bias for standard resolution, high spatial resolution, and ultrahigh spatial resolution, respectively: 10.1%, 8.0%, and 2.3%; P < .001). In vivo results confirmed decreasing median percentage DS with increasing spatial resolution for calcified stenoses (n = 161) (standard resolution, high spatial resolution, and ultrahigh spatial resolution, respectively: 41.5% [IQR, 27.3%-58.2%], 34.8% [IQR, 23.7%-55.1%], and 26.7% [IQR, 18.6%-44.3%]; P < .001), whereas noncalcified (n = 13) and mixed plaques (n = 19) did not show evidence of a difference (P ≥ .88). Ultrahigh-spatial-resolution reconstructions led to reclassification of 62 of 114 (54.4%) patients to lower CAD-RADS category than that assigned using standard resolution. Conclusion In vivo and in vitro coronary stenosis assessment improved for calcified stenoses by using ultrahigh-spatial-resolution PCD CT reconstructions, leading to lower percentage DS compared with standard resolution and clinically relevant rates of reclassification. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by McCollough in this issue.

Everolimus eluting bioresorbable vascular scaffolds in patients with acute coronary syndromes: Two-year results from the German-Austrian ABSORB registry.

OBJECTIVES: To identify potential differences in 2-year outcome between patients who underwent coronary revascularization using bioresorbable vascular scafffolds (BVS) in stable coronary artery disease (CAD) and acute coronary syndromes (ACS). BACKGROUND: Data from randomized trials suggest a significantly higher event rate following coronary revascularization using everolimus-eluting BVS as compared to new generation drug eluting stents. Whether particular patient subgroups are at increased risk for scaffold thrombosis and target lesion failure (TLF) has not clearly been demonstrated. METHODS: German-Austrian ABSORB RegIstRy is a prospective all-comer multi-center observational study of consecutive patients who were considered for coronary revascularization with BVS. We compared 1499 patients with stable CAD to 1594 patients with ACS. Endpoints were major adverse cardiac events (MACE), TLF, and scaffold thrombosis. RESULTS: While single vessel disease was more prevalent in ACS (46% vs. 37%, p < 0.0001), lesion complexity (B2/C stenosis 37% vs. 36%, bifurcation 2.4% vs. 3.4%, p < 0.05), number of implanted scaffolds/patient (1.34 vs. 1.43), scaffold length (18 vs. 18 mm) or the rate of high pressure postdilatation (68% vs. 70%) did not differ between ACS and stable CAD. Two-year MACE rates were 11.6% in ACS and 11.4% in stable CAD, TLF occurred in 7.0% versus 7.4% and target vessel revascularization in 8.8 versus 10.2% (n.s. for all). Definite scaffold thrombosis rates were not significantly different (ACS 1.9% vs. stable CAD 2.1%). CONCLUSION: Real-world 2-year event rates after coronary revascularization with BVS are not significantly different between individuals with ACS as compared to stable CAD.

Restenosis patterns after bioresorbable vascular scaffold implantation: Angiographic substudy of the GHOST-EU registry.

OBJECTIVES: To evaluate pattern of in-BVS-restenosis after bioresorbable vascular scaffold (BVS) implantation. BACKGROUND: In-stent restenosis morphology impacts target lesion revascularization (TLR) rates and clinical outcomes. Although several trials report on outcomes after BVS implantation, information about in-BVS restenosis pattern is still lacking. METHODS: Between November 2011 and January 2014, in 7 of 10 European centers participating in the GHOST-EU registry, 668 patients underwent BVS implantation. Of them 164 patients (200 lesions) underwent an additional angiogram 3 to 12 months after index PCI. RESULTS: Binary in-BVS restenosis (IBR) (in-segment diameter stenosis ≥50%) was observed in 12.7% (21 of 164) of patients (30 lesions), with a TLR rate of 16.5%. The IBR morphology was classified as focal margin in 50.0%, focal body in 26.7%, multifocal in 10.0%, and diffuse in 13.3% of these cases. Treatment of small vessels (OR 5.49, 95% CI 1.6-18.8, P < 0.01) was identified as independent predictor of IBR. Performing predilatation (OR 0.13, 95% CI 0.02-1.04, P = 0.06), high-pressure postdilatation (OR 3.16, 95% CI 0.90-11.18, P = 0.07) as well as treatment of acute coronary syndrome (OR 0.18, 95% CI 0.03-1.12, P = 0.07) seem to strongly influence this risk. CONCLUSIONS: The IBR morphology is mostly focal involving particularly the BVS margins suggesting association with procedural aspects in this early experience with BVS. Treatment of small vessels is the strongest predictor of higher IBR risk.